Bcma-targeted car-t cell therapy of multiple myeloma

Abstract

A method for assessing responsiveness of a subject to a treatment comprising T cells expressing a bivalent BCMA-targeting chimeric antigen receptor (CAR), comprising administering to the subject the T cells, and assessing the responsiveness of the subject to the treatment based on time length the subject maintains minimal residual disease (MRD) negative status.

1 . A method for assessing responsiveness of a subject to a treatment comprising T cells expressing a bivalent BCMA-targeting chimeric antigen receptor (CAR), comprising:
 (a) administering to the subject the T cells;   (b) measuring time length the subject maintains minimal residual disease (MRD) negative status; and   (c) assessing the responsiveness of the subject to the treatment based on that
 (i) the MRD negative status is maintained for shorter than 6 months; 
 (ii) the MRD negative status is maintained for at least 6 months and shorter than 12 months; or 
 (iii) the MRD negative status is maintained for at least 12 months, wherein the bivalent BCMA-targeting CAR comprises an extracellular antigen binding domain comprising a first VHH domain and a second VHH domain, a transmembrane domain, and an intracellular signaling domain, wherein the first VHH domain comprising a CDR1, a CDR2, and a CDR3 as set forth in the VHH domain comprising the amino acid sequence of SEQ ID NO: 2, and the second VHH domain comprising a CDR1, a CDR2, and a CDR3 as set forth in the VHH domain comprising the amino acid sequence of SEQ ID NO: 4. 
   
     
     
         2 . The method of  claim 1 , wherein the first VHH domain comprises a CDR1 comprising the amino acid sequence of SEQ ID NO: 18, a CDR2 comprising the amino acid sequence of SEQ ID NO: 19, a CDR3 comprising the amino acid sequence of SEQ ID NO: 20; and the second VHH domain comprises a CDR1 comprising the amino acid sequence of SEQ ID NO: 21, a CDR2 comprising the amino acid sequence of SEQ ID NO: 22, and a CDR3 comprising the amino acid sequence of SEQ ID NO: 23. 
     
     
         3 . The method of  claim 1 , wherein the first VHH domain comprises the amino acid sequence of SEQ ID NO: 2 and the second VHH domain comprises the amino acid sequence of SEQ ID NO: 4. 
     
     
         4 . The method of  claim 1 , wherein the first VHH domain is at the N-terminus of the second VHH domain, or the first VHH domain is at the C-terminus of the second VHH domain, wherein optionally the first VHH domain is linked to the second VHH domain via a linker comprising the amino acid sequence of SEQ ID NO: 3. 
     
     
         5 . (canceled) 
     
     
         6 . The method of  claim 1 , wherein the transmembrane domain is derived from a molecule selected from the group consisting of CD8a, CD4, CD28, CD137, CD80, CD86, CD152 and PD1, wherein optionally the transmembrane domain is derived from CD8a and comprises the amino acid sequence of SEQ ID NO: 6. 
     
     
         7 . (canceled) 
     
     
         8 . The method of  claim 1 , wherein:
 (1) the intracellular signaling domain comprises a primary intracellular signaling domain of an immune effector cell, wherein optionally the primary intracellular signaling domain is derived from CD3ζ comprising the amino acid sequence of SEQ ID NO: 8: or   (2) the intracellular signaling domain comprises a co-stimulatory signaling domain, wherein optionally the co-stimulatory signaling domain is derived from a co-stimulatory molecule selected from the group consisting of CD27, CD28, CD137, OX40, CD30, CD40, CD3, LFA-1, ICOS, CD2, CD7, LIGHT, NKG2C, B7-H3, ligands of CD83 and any combination thereof, wherein further optionally the co-stimulatory signaling domain comprises a cytoplasmic domain of CD137 comprising the amino acid sequence of SEQ ID NO: 7.   
     
     
         9 - 12 . (canceled) 
     
     
         13 . The method of  claim 1 , wherein the CAR further comprises:
 (1) a hinge domain located between the C-terminus of the extracellular antigen binding domain and the N-terminus of the transmembrane domain, wherein optionally the hinge domain is derived from CD8a comprising the amino acid sequence of SEQ ID NO: 5; or   (2) a signal peptide located at the N-terminus of the polypeptide, wherein optionally the signal peptide is derived from CD8a comprising the amino acid sequence of SEQ ID NO: 1.   
     
     
         14 - 16 . (canceled) 
     
     
         17 . The method of  claim 1 , wherein the CAR comprises the amino acid sequence of SEQ ID NO: 17. 
     
     
         18 . The method of  claim 1 , wherein the subject has a disease or disorder, wherein optionally the disease or disorder is cancer, wherein further optionally the cancer is multiple myeloma, and wherein further optionally the cancer is refractory or relapsed multiple myeloma. 
     
     
         19 - 21 . (canceled) 
     
     
         22 . The method of  claim 1 , wherein the method comprises obtaining bone marrow aspirate or biopsy from the subject for assessing MRD status, wherein optionally the MRD status is monitored using next generation sequencing (NGS) of bone marrow aspirate DNA, wherein further optionally the NGS is performed via clonoSEQ. 
     
     
         23 - 24 . (canceled) 
     
     
         25 . The method of  claim 22 , wherein baseline bone marrow aspirates are used to define the myeloma clones, and post-treatment samples are used to evaluate MRD negativity, wherein optionally evaluable samples are those that passed one or more of, or all of, calibration, quality control, and sufficiency of cells evaluable at a particular sensitivity level, wherein further optionally the sensitivity level is about 10 −6 , 10 −5 ,  10   −4 , or 10 −3 . 
     
     
         26 - 27 . (canceled) 
     
     
         28 . The method of  claim 1 , wherein the time length the subject maintains MRD negative status is measured from the time when MRD is first achieved in the subject. 
     
     
         29 . The method of  claim 1 , wherein the method comprises assessing the likelihood of the subject to have complete response (CR), partial response (PR), stringent CR (sCR), or very good PR (VGPR). 
     
     
         30 . The method of  claim 29 , comprising determining that the subject is likely to have CR, PR, sCR, or VGPR if the MRD negative status is maintained for shorter than 6 months in the subject, or determining that the subject is likely to have CR or sCR if the MRD negative status is maintained for longer than 6 months in the subject. 
     
     
         31 . (canceled) 
     
     
         32 . The method of  claim 1 , wherein the method comprises assessing the likelihood of the subject to have progression-free survival. 
     
     
         33 . The method of  claim 32 , comprising determining that the subject is likely to have progression-free survival for at least 12 months post the treatment if the MRD negative status is maintained for longer than 6 months in the subject. 
     
     
         34 . The method of  claim 32 , comprising determining that the subject is likely to have progression-free survival for at least 24 months post the treatment if the MRD negative status is maintained for longer than 12 months in the subject. 
     
     
         35 . The method of  claim 1 , wherein the method comprises assessing duration of response in the subject. 
     
     
         36 . The method of  claim 35 , comprising determining that the subject is likely to have a duration of response of more than 12 months if the MRD negative status is maintained for longer than 6 months in the subject. 
     
     
         37 . The method of  claim 36 , comprising determining that the subject is likely to have a duration of response of more than 24 months if the MRD negative status is maintained for longer than 12 months in the subject.